From black holes to emergent gravity

Many inequivalent approaches to study black holes yield identical results. Any meaningful theory of gravity should explain the origin of this property. Here we show that the basic holomorphic modes characterising the underlying two dimensional conformal symmetry near the horizon bring about this universality. Moreover these modes lead to a law of equipartition of energy for black holes which suggests a statistical origin of gravity. This emergent nature of gravity is further bolstered by showing the equivalence of entropy with the action $\left(S=-\frac{i}{\hbar}\,I\right)$ and expressing the generalised Smarr formula for mass as a thermodynamic relation, $S=\frac{E}{2T}$ where $S$, $E$ and $T$ are the entropy, energy and temperature, respectively, of a black hole.Comment: Latex, 6 pages, Gravity Research Foundation essay 2010 (Received Honorable Mention

Interrogating Identity Construction: Bodies versus Community in Cynthia Kadohatas In the Heart of the Valley of Love

In an interview for the journal MELUS, Hsiu-chuan Lee claims that Cynthia Kadohata suggests her novel In the Heart of the Valley of Love does not directly take any specific ethnicity as its central concern, nor deal explicitly with the identity issue (165, 179). Despite these assertions by the author, In the Heart of the Valley of Love is mainly taught at the university level in Asian American Literature courses. While Kadohatas novel has been established within this specific canon of Asian American Literature, her novel deals with issues that resonate among all racial groups. This paper considers the ways in which Kadohata creates an imagined future not wholly detached from issues of race and identity, but where the conceptualization of race-based identity is conceived by means of self-fashioning and self-signifying. In the novels futuristic American society, concerns of class and the divides of wealth between the white richtowns and the multiracial majority may seem to be the central themes, but issues of race and issues of class become conflated in the novel, and Kadohata uses more subtle ways to discuss issues of racial difference. What Kadohata suggests through her novel In the Heart of the Valley of Love is not that racialized bodies cease to be of importance in American society, but that race as a critical factor in identity formation and categorization must be reframed by self-signification and social interactions

Risk Aversion and Expected-Utility Theory: A Calibration Theorem

Within the expected-utility framework, the only explanation for risk aversion is that the utility function for wealth is concave: A person has lower marginal utility for additional wealth when she is wealthy than when she is poor. This paper provides a theorem showing that expected-utility theory is an utterly implausible explanation for appreciable risk aversion over modest stakes: Within expected-utility theory, for any concave utility function, even very little risk aversion over modest stakes implies an absurd degree of risk aversion over large stakes. Illustrative calibrations are provided.

Cross-linking patterns and their images in swollen and deformed gels

Using the theory of elasticity of polymer gels we show that large-scale cross-link density patterns written into the structure of the network in the melt state, can be revealed upon swelling by monitoring the monomer density patterns. We find that while isotropic deformations in good solvent yield magnified images of the original pattern, anisotropic deformations distort the image (both types of deformation yield affinely stretched images in $\theta$ solvents). We show that in ordinary solids with spatially inhomogeneous profile of the shear modulus, isotropic stretching leads to distorted density image of this profile under isotropic deformation. Using simple physical arguments we demonstrate that the different response to isotropic stretching stems from fundamental differences between the theory of elasticity of solids and that of gels. Possible tests of our predictions and some potential applications are discussed.Comment: 16 pages, 3 figure

Experiences and Thoughts on STEMTEC-Inspired Changes in Teaching Physics for Life Science Majors

I have taught an introductory course for life science majors three times, each time introducing one or more teaching techniques discussed during the Science, Technology, Engineering, and Mathematics Teaching Education Collaborative (STEMTEC) meetings. Typical class size was 275 students. I cannot make quantitative statements about comparisons between the results of STEMTEC-type teaching methods and traditional teaching methods because I have never taught this course in a completely traditional lecture style. During the first year, I introduced conceptual questions into my lectures. The lecture would be interrupted several times with questions posed to the class. The students then had several minutes to discuss each question among their neighbors, then present their answers. During the second year, I switched from traditional homework to a computerized system which allowed instant feedback to the students, and the ability to resubmit solutions to problems they had not successfully solved. I also introduced an exam format that enabled the students to work individually, then redo the exam in groups and hand in a second set of solutions. The goal of each of these techniques was to increase the engagement of the students with the material of the course. Each of the techniques had both successes and limitations. The most serious problems I confronted were technical difficulties which diverted attention from the tasks at hand to the necessity of keeping the system functioning